c8_31pf.cpp

实现3GPP的GSM中AMR语音的CODECS。

/* ------------------------------------------------------------------
 * Copyright (C) 2008 PacketVideo
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 * -------------------------------------------------------------------
 */
/****************************************************************************************
Portions of this file are derived from the following 3GPP standard:

    3GPP TS 26.073
    ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
    Available from http://www.3gpp.org

(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
Permission to distribute, modify and use this file under the standard license
terms listed above has been obtained from the copyright holder.
****************************************************************************************/
/*
------------------------------------------------------------------------------



 Pathname: ./audio/gsm-amr/c/src/c8_31pf.c
 Functions:

     Date: 05/26/2000

------------------------------------------------------------------------------
 REVISION HISTORY

 Description: Modified to pass overflow flag through to basic math function.
 The flag is passed back to the calling function by pointer reference.

 Description: Optimized file to reduce clock cycle usage. Updated copyright
              year. Removed unnecessary include files and unused #defines.

 Description: Changed round function name to pv_round to avoid conflict with
              round function in C standard library.

 Description:  Replaced "int" and/or "char" with OSCL defined types.

 Description:

------------------------------------------------------------------------------
 MODULE DESCRIPTION

 Purpose          : Searches a 31 bit algebraic codebook containing
                  : 8 pulses in a frame of 40 samples.
                  : in the same manner as GSM-EFR
------------------------------------------------------------------------------
*/

/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "c8_31pf.h"
#include "typedef.h"
#include "cnst.h"
#include "inv_sqrt.h"
#include "cor_h.h"
#include "cor_h_x2.h"
#include "set_sign.h"
#include "s10_8pf.h"
#include "basic_op.h"

/*----------------------------------------------------------------------------
; MACROS
; Define module specific macros here
----------------------------------------------------------------------------*/

/*----------------------------------------------------------------------------
; DEFINES
; Include all pre-processor statements here. Include conditional
; compile variables also.
----------------------------------------------------------------------------*/
#define NB_PULSE 8

/* define values/representation for output codevector and sign */
#define POS_CODE  8191
#define NEG_CODE  8191
#define POS_SIGN  32767
#define NEG_SIGN  (Word16) (-32768L)

/*----------------------------------------------------------------------------
; LOCAL FUNCTION DEFINITIONS
; Function Prototype declaration
----------------------------------------------------------------------------*/

/*----------------------------------------------------------------------------
; LOCAL VARIABLE DEFINITIONS
; Variable declaration - defined here and used outside this module
----------------------------------------------------------------------------*/

/*----------------------------------------------------------------------------
; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
; Declare variables used in this module but defined elsewhere
----------------------------------------------------------------------------*/

/*
------------------------------------------------------------------------------
 FUNCTION NAME:
------------------------------------------------------------------------------
 INPUT AND OUTPUT DEFINITIONS

 Inputs:
    codvec[]   Array of type Word16 -- position of pulses
    sign[]     Array of type Word16 -- sign of pulses
    h[]        Array of type Word16 -- impulse response of
                                       weighted synthesis filter
 Outputs:
    cod[]       Array of type Word16 -- innovative code vector
    y[]         Array of type Word16 -- filtered innovative code
    sign_indx[] Array of type Word16 -- signs of 4 pulses (signs only)
    pos_indx[]  Array of type Word16 --
                             position index of 8 pulses(position only)

    pOverflow  Pointer to Flag  -- set when overflow occurs

 Returns:
    indx

 Global Variables Used:
    None

 Local Variables Needed:

------------------------------------------------------------------------------
 FUNCTION DESCRIPTION


------------------------------------------------------------------------------
 REQUIREMENTS

 None

------------------------------------------------------------------------------
 REFERENCES

 [1] c8_31pf.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001

------------------------------------------------------------------------------
 PSEUDO-CODE

------------------------------------------------------------------------------
 RESOURCES USED [optional]

 When the code is written for a specific target processor the
 the resources used should be documented below.

 HEAP MEMORY USED: x bytes

 STACK MEMORY USED: x bytes

 CLOCK CYCLES: (cycle count equation for this function) + (variable
                used to represent cycle count for each subroutine
                called)
     where: (cycle count variable) = cycle count for [subroutine
                                     name]

------------------------------------------------------------------------------
 CAUTION [optional]
 [State any special notes, constraints or cautions for users of this function]

------------------------------------------------------------------------------
*/

/*************************************************************************
 *
 *  FUNCTION:  build_code()
 *
 *  PURPOSE: Builds the codeword, the filtered codeword and a
 *   linear uncombined version of  the index of the
 *           codevector, based on the signs and positions of 8  pulses.
 *
 *************************************************************************/

static void build_code(
    Word16 codvec[],    /* i : position of pulses                           */
    Word16 sign[],      /* i : sign of d[n]                                 */
    Word16 cod[],       /* o : innovative code vector                       */
    Word16 h[],         /* i : impulse response of weighted synthesis filter*/
    Word16 y[],         /* o : filtered innovative code                     */
    Word16 sign_indx[], /* o : signs of 4  pulses (signs only)              */
    Word16 pos_indx[],  /* o : position index of 8 pulses(position only)    */
    Flag   * pOverflow  /* o : Flag set when overflow occurs                */
)
{
    Word16 i;
    Word16 j;
    Word16 k;
    Word16 track;
    Word16 sign_index;
    Word16 pos_index;
    Word16 _sign[NB_PULSE];

    Word16 *p0;
    Word16 *p1;
    Word16 *p2;
    Word16 *p3;
    Word16 *p4;
    Word16 *p5;
    Word16 *p6;
    Word16 *p7;

    Word16 *p_cod = &cod[0];
    Word16 *p_codvec = &codvec[0];

    Word32 s;

    for (i = 0; i < L_CODE; i++)
    {
        *(p_cod++) = 0;
    }

    for (i = 0; i < NB_TRACK_MR102; i++)
    {
        pos_indx[i] = -1;
        sign_indx[i] = -1;
    }

    for (k = 0; k < NB_PULSE; k++)
    {
        /* read pulse position */
        i = codvec[k];
        /* read sign           */
        j = sign[i];

        pos_index = i >> 2; /* index = pos/4 */

        track = i & 3;     /* track = pos%4 */

        if (j > 0)
        {
            cod[i] = (Word16)((Word32) cod[i] + POS_CODE);

            _sign[k] = POS_SIGN;
            sign_index = 0;  /* bit=0 -> positive pulse */
        }
        else
        {
            cod[i] = (Word16)((Word32) cod[i] - NEG_CODE);

            _sign[k] = NEG_SIGN;
            sign_index = 1; /* bit=1 => negative pulse */
            /* index = add (index, 8); 1 = negative  old code */
        }

        if (pos_indx[track] < 0)
        {   /* first set first NB_TRACK pulses  */
            pos_indx[track] = pos_index;
            sign_indx[track] = sign_index;
        }
        else
        {   /* 2nd row of pulses , test if positions needs to be switched */
            if (((sign_index ^ sign_indx[track]) & 1) == 0)
            {
                /* sign of 1st pulse == sign of 2nd pulse */

                if (pos_indx[track] <= pos_index)
                {   /* no swap */
                    pos_indx[track + NB_TRACK_MR102] = pos_index;
                }
                else
                {   /* swap*/
                    pos_indx[track + NB_TRACK_MR102] = pos_indx[track];

                    pos_indx[track] = pos_index;
                    sign_indx[track] = sign_index;
                }
            }
            else
            {
                /* sign of 1st pulse != sign of 2nd pulse */

                if (pos_indx[track] <= pos_index)
                {  /*swap*/
                    pos_indx[track + NB_TRACK_MR102] = pos_indx[track];

                    pos_indx[track] = pos_index;
                    sign_indx[track] = sign_index;
                }
                else
                {   /*no swap */
                    pos_indx[track + NB_TRACK_MR102] = pos_index;
                }
            }
        }
    }

    p0 = h - *(p_codvec++);
    p1 = h - *(p_codvec++);
    p2 = h - *(p_codvec++);
    p3 = h - *(p_codvec++);
    p4 = h - *(p_codvec++);
    p5 = h - *(p_codvec++);
    p6 = h - *(p_codvec++);
    p7 = h - *(p_codvec);

    for (i = 0; i < L_CODE; i++)
    {
        s = 0;

        s =
            L_mac(
                s,
                *p0++,
                _sign[0],
                pOverflow);
        s =
            L_mac(
                s,
                *p1++,
                _sign[1],
                pOverflow);
        s =
            L_mac(
                s,
                *p2++,
                _sign[2],
                pOverflow);
        s =
            L_mac(
                s,
                *p3++,
                _sign[3],
                pOverflow);
        s =
            L_mac(
                s,
                *p4++,
                _sign[4],
                pOverflow);
        s =
            L_mac(
                s,
                *p5++,
                _sign[5],
                pOverflow);
        s =
            L_mac(
                s,
                *p6++,
                _sign[6],
                pOverflow);
        s =
            L_mac(
                s,
                *p7++,
                _sign[7],
                pOverflow);

        y[i] =
            pv_round(
                s,
                pOverflow);

    } /* for (i = 0; i < L_CODE; i++) */

} /* build_code */

/****************************************************************************/

/*
------------------------------------------------------------------------------
 FUNCTION NAME: compress_code()
------------------------------------------------------------------------------
 INPUT AND OUTPUT DEFINITIONS

 Inputs:

 Outputs:

 Returns:
    None

 Global Variables Used:
    None

 Local Variables Needed:

------------------------------------------------------------------------------
 FUNCTION DESCRIPTION

 FUNCTION:

 PURPOSE: compression of three indeces [0..9] to one 10 bit index
          minimizing the phase shift of a bit error.

------------------------------------------------------------------------------
 REQUIREMENTS

 None

------------------------------------------------------------------------------
 REFERENCES

 [1] c8_31pf.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001

------------------------------------------------------------------------------
 PSEUDO-CODE

------------------------------------------------------------------------------
 RESOURCES USED [optional]